Each chapter starts with an overview. Think of it as a roadmap to help you get oriented and make the most of your studying.

《 LOOKING BACK A Looking Back reference tells you what material from previous chapters is especially important for understanding the new topics. A quick review will help your learning. You will find additional Looking Back references within the chapter, right at the point they’re needed.

Before solving motion problems, we must learn to describe motion. We will use

• Motion diagrams

• Graphs

• Pictures

Motion concepts introduced in this chapter include position, velocity, and acceleration.

Many of the quantities used to describe motion, such as velocity, have both a size and a direction. We use vectors to represent these quantities. This chapter introduces graphical techniques to add and subtract vectors. Chapter 3 will explore vectors in more detail.

Scientists and engineers must communicate their ideas to others. To do so, we have to agree about the units in which quantities are measured. In physics we use metric units, called SI units. We also need rules for telling others how accurately a quantity is known. You will learn the rules for using significant figures correctly.

The universe is in motion, from the smallest scale of electrons and atoms to the largest scale of entire galaxies. We’ll start with the motion of everyday objects, such as cars and balls and people. Later we’ll study the motions of waves, of atoms in gases, and of electrons in circuits. Motion is the one theme that will be with us from the first chapter to the last.